One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,8)(6,7)(9,10)(11,14)(12,19)(13,15)(16,21)(17,23)(18,24)(20,22)(25,26,31,28)(27,34,30,32)(29,33,38,36)(35,40,37,39)(1,3)(2,8)(4,6)(5,7)(9,11,13,17)(10,14,15,23)(12,20,21,18)(16,24,19,22)(25,26,31,28)(27,32,30,34)(29,36,38,33)(35,40,37,39)(1,2,7,6)(3,8,5,4)(10,15)(11,17)(16,19)(18,20)(25,27,31,30)(26,32,28,34)(29,35,38,37)(33,39,36,40)(1,4)(2,5)(3,6)(7,8)(9,10)(11,14)(12,16)(13,15)(17,23)(18,22)(19,21)(20,24)(25,28,31,26)(27,34,30,32)(29,36,38,33)(35,40,37,39)(1,5,7,3)(2,8,6,4)(9,11)(10,14)(12,18)(13,17)(15,23)(16,22)(19,24)(20,21)(25,29,31,38)(26,33,28,36)(27,35,30,37)(32,39,34,40)(1,6,7,2)(3,8,5,4)(9,12,13,21)(10,16,15,19)(11,18,17,20)(14,22,23,24)(25,30,31,27)(26,34,28,32)(29,37,38,35)(33,40,36,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.